Dark antibacterial activity of rose Bengal

Faina Nakonechny, Margarita Barel, Arad David, Simor Koretz, Boris Litvak, Elena Ragozin, Ariel Etinger, Oz Livne, Yosef Pinhasi, Gary Gellerman, Marina Nisnevitch

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


The global spread of bacterial resistance to antibiotics promotes a search for alternative approaches to eradication of pathogenic bacteria. One alternative is using photosensitizers for inhibition of Gram-positive and Gram-negative bacteria under illumination. Due to low penetration of visible light into tissues, applications of photosensitizers are currently limited to treatment of superficial local infections. Excitation of photosensitizers in the dark can be applied to overcome this problem. In the present work, dark antibacterial activity of the photosensitizer Rose Bengal alone and in combination with antibiotics was studied. The minimum inhibitory concentrations (MIC) value of Rose Bengal against S. aureus dropped in the presence of sub-MIC concentrations of ciprofloxacin, levofloxacin, methicillin, and gentamicin. Free Rose Bengal at sub-MIC concentrations can be excited in the dark by ultrasound at 38 kHz. Rose Bengal immobilized onto silicon showed good antibacterial activity in the dark under ultrasonic activation, probably because of Rose Bengal leaching from the polymer during the treatment. Exposure of bacteria to Rose Bengal in the dark under irradiation by electromagnetic radio frequency waves in the 9 to 12 GHz range caused a decrease in the bacterial concentration, presumably due to resonant absorption of electromagnetic energy, its transformation into heat and subsequent excitation of Rose Bengal.

Original languageEnglish
Article number3196
JournalInternational Journal of Molecular Sciences
Issue number13
StatePublished - 1 Jul 2019


  • Immobilization
  • Radio wave activation
  • Rose Bengal
  • S. aureus
  • Silicon
  • Ultrasonic excitation


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